The present disclosure relates to a control device, storage device, and storage control method and in particular to processing of management information for logical-to-physical block address conversion.
Storage devices using a non-volatile memory, such as a NAND flash memory, are being widely used. A non-volatile memory is being used in memory cards, solid state drives (SSDs), embedded multimedia cards (eMMCs), and the like used in, for example, electronic devices, information processing devices, and the like.
Japanese Unexamined Patent Application Publication Nos. 2009-70098, 2007-334852, 2007-193838, and 2007-58840 disclose storage devices using a flash memory.
In a non-volatile memory, physical block addresses (PBAs) are used as the addresses of physical storage areas. A physical block address is composed of a physical block, a physical page, and a physical sector. Multiple physical sectors form a physical page, and multiple physical pages form a physical block.
While erase is performed on a physical block basis, write (program) and read can be performed on a physical page basis.
The host or memory control unit specifies an address using a logical block address (LBA). A logical block address composed of a logical block and a logical page is associated with the above-mentioned physical block address. Thus, when access is requested, a logical block address is converted into a physical block address, so that access is actually made to the flash memory.